/**
 * createTime: 2012-12-12
 */

//处理tree select下拉方向固定问题
Ext.form.TreeField.prototype.expand=function() {
	if (this.isExpanded() || !this.hasFocus) {
		return;
	}
	Ext.menu.MenuMgr.unregister(this.menu);
	this.menu.show(this.el, 'tl-bl?'); // tl-bl?
	// Fix Bug, when using checkbox selection model
	if (this.getPath() != "") {
		this.menu.picker.tree.selectPath(this.getPath(), null);
	}
	this.el.focus();
	Ext.get(document).on('mousedown', this.collapseIf, this);
	this.fireEvent('expand', this);
};